Hi, noob at circuitry here. My video equipment happens to use a standard 9v 300mA DC input, but if I want to use it wirelessly the battery dies pretty quickly. So I came up with an idea to build a rechargeable battery pack of my own, after seeing that the other alternative was a $50 flat battery pack. I took inspiration from the MacBook Air external battery thread. Using this 9.9v battery and this resistor I calculated that the output would be 9v 300mA. Did I do it right? Also, on the battery, there's four cables. The red and black are obviously the outbound +/- connections. But then there's the red and yellow connectors that I can't identify what their uses are. Just like the rechargeable Air battery, I'll be using this charger but I don't know how to connect it. Can someone help me put all these together? I'm trying to learn this stuff which might come in handy for other DIY power supplies. Thanks!